Processing elements for mixing meat products

ABSTRACT

A continuous method and system for processing whole muscle meat employs a mixer housing having a pair of parallel rotating shafts located therein. The parallel rotating shafts have a plurality of mixing elements thereon, such as frustoconical elements, blocking elements, or ellipsoid elements. The mixer housing has an input end to receive the meat ingredients, such as meat pieces, salt solution, water, preservatives, and other additives such as spices. The mixer housing has an output, which is separated a distance from the input, such that the output discharges the whole muscle meat product. As the ingredients including the meat move from the input to the output along the shafts, the mixing elements work the meat with the other ingredients thereby increasing ingredient incorporation including diffusion of the salt solution into the whole muscle meat pieces.

TECHNICAL FIELD

This invention relates generally to a method and apparatus forprocessing meat and, in particular, to processing meat in a continuousprocesses.

BACKGROUND

Processed meat products, such as bologna, hot dogs, sausages, and wholemuscle products including ham and turkey, among many others, areconvenient and popular food items. A variety of commercial systems areavailable for making certain processed meats. In one type of commercialsystem used for making processed meat products including bologna and hotdogs, raw meat in the form of chunks or pieces and other ingredientssuch as spices are ground, chopped and/or otherwise blended with one ormore salt solutions or brine to provide a mixture that can subsequentlybe formed into a stable meat emulsion or protein matrix. Similar stepsof grinding, chopping and/or otherwise working are also employed inmaking coarse ground products such as sausages, whole muscle productssuch as processed ham and processed turkey and other processed meats. Ineach case, proteins form a matrix to hold or bond the separate meatpieces together.

A stable protein matrix requires the protein bonds to suspend or bondwith fat and water. Creation of protein bonds in this context requires aprocess commonly known as protein extraction. In this process, saltsoluble or salt extractable, heat coagulable proteins such as myosin,actomyosin, and actin bind water, swell and become tacky as a result ofworking or blending of the meat in the presence of a salt or a saltsolution. The proteins are subsequently set when heated to create abond. Other myofibrillar proteins, as well as sarcoplasmic or watersoluble or extractable proteins, may also play a role in bonding. Saltsolutions that may be used in protein extraction include, but are notlimited to, sodium chloride, sodium pyrophosphate or diphosphate,potassium chloride, sodium lactate, and potassium lactate. In proteinextraction as described herein, the mechanism believed to be primaryresponsible for the creation of the bonds involves binding proteins,salts, fats, and/or water and subsequent swelling of the proteins,rather than solution of the proteins. More precisely, it is believedthat the salt solution frees bonding sites on the proteins for bondingwith each other, as well as with water and fat.

Batch processes for blending meat and other ingredients and extractingprotein are well known. A known method for achieving protein extractionand ingredient blending for certain products such as whole muscle meatsincluding processed turkey and processed ham involves puncturing thewhole muscle meat with hypodermic-type needles, injecting brine or saltsolution through the needles, and using a batch processor or mixer towork the meat for approximately 45 minutes under vacuum conditions toremove air, as discussed below. For other products such as coarse groundmeat including sausages and emulsified products, meat is ground andadded to a batch processor with water, salt solution, spices, and/orother ingredients and worked with or without a vacuum for up to an hour,or in one approach, for 15 to 45 minutes.

A large batch mixer may process approximately 6,000 to 12,000 pounds perhour. The meat product constituents including the meats and theadditives are combined in the low shear batch mixer for whole muscleproducts. This mixing stage typically requires 30 to 60 minutes of beingmixed. It is during this time that the constituents are transformed intoa mixture that will form a stable protein matrix.

A stable protein matrix is formed when mixtures for whole muscleproducts, coarse ground products, and emulsified products allow the saltsolution to reach the salt-extractable protein. The time it takes forthe salt to reach the salt-extractable protein may vary and it isdesirable to decrease the time it takes for the process to occur. Thisprocess, known as curing, achieves the protein extraction. For wholemuscle products, delivery of the brine solution through injection of thehypodermic-type needles inserted into the meat chunks is a relativelyimprecise method for attempting to reduce the distance through which thesalt solution must diffuse. The curing stage typically requires 24-48hours for satisfactory diffusion, and the batches are stored in vats andplaced into coolers for the cure time. Once the protein extraction hasoccurred, the mixture may then be further processed.

With respect to the processing equipment, while such mixers have beenused commercially for many years, they have significant drawbacks withrespect to their space requirements and cost due to their large size, aswell as the length of time required for processing each batch, and thetime and expense associated with cleaning of the apparatus.

As for the process, conventional batch processing is a lengthy processrequiring a number of discrete steps. Initially, various meats areprovided by a vendor with specified contents. More specifically, themeats are provided with a specified protein, fat, and/or water content,typically a percentage by weight. A batch sheet is provided toprocessing plant personnel indicating what mixture of meats, water, andadditives are to be combined for one of a variety of meat products. Inaddition, the batch sheet often needs to be adjusted or more preciselyindicated after the batch of meat has arrived at the plant. Based on theformula desired for the final meat product, the plant personnel oftenhave to adjust the meats selected for processing in a particular batch.The final product mixture is carefully controlled. If a particular meatis utilized where the fat content is greater than what the batch sheetcalls for, the final product may have an excessive amount of fat. Toavoid this, the plant personnel would increase the protein provided byother meats to balance the fat content.

Unfortunately, this is not necessarily a sufficiently precise approach.Each meat, as well as each chunk in a batch of meat, may varysignificantly from a sample taken and assumed to be average. Once thewater and other additives are mixed in with the batch, it may bedifficult to alter the balance. At times, the resulting batch isdetermined to be inaccurately mixed, and remedial procedures must betaken such as mixing the batch in with additional correction materials.In order to reduce the likelihood of an imprecise batch, relativelylarge quantities of meat are provided for a single batch in hopes ofminimizing or driving to a mean the composition deviation resulting froma meat portion with an aberrational content. A typical amount of aparticular meat for a batch is approximately 2000 lbs.

Input constituents are calculated to result in a specific quantity ofcooked product. If excessive water or fat is lost post-mix such asduring the cook stage, the carefully regulated water, fat, and meatratios will be off-target. If fat is lost prior to the cook stage, itoften remains in the machinery or piping through which the mixture isprocessed. This can result in down time for the machinery, likelihood ofdamaged machinery, and greater labor in cleaning the machinery.Furthermore, cooked emulsified products rely, to some degree, onnon-protein or non-bound materials to provide the proper texture. Theproteins bind to form a matrix with each other and, in the absence ofsufficient fat or water, these bonds may form a larger, stronger matrix,which leads the product to become somewhat rubbery. Conversely, if thereis too much water, the cooked product may be too soft, and may lackintegrity.

As used herein, the term additives may refer broadly to brine solution,water without salt, a spice slurry, nitrite, or other additives. Thoughthe brine solution and the meats themselves each include water, thebalance for the final product is typically adjusted with a quantity ofwater. The spice slurry provides, for instance, flavorings and water.One additive is typically nitrite which is used as a preservative and toprovide a desired color. Other inert additives, such as corn starch ornon-functional proteins, may also be included.

As the mixture constituents are churned in the mixer for up to an hour,contact with air may produce a froth on the surface of the meat pieces.A final product having visible air may be unacceptable. In some cases,the product must be reprocessed and mixed in with subsequent batches.Air in the product may appear as surface bubbles, or as surface holes.Entrapped air may also lead to product swelling during cooking or maylead to the product having visible air bubbles within its interior.

Air affects the product in other ways as well. For instance, someproteins are denatured by the presence of air, which reduces thefunctionality of the meat for binding fat and water. The air can alsoreact with the nitrite to retard the development of the proper color.The resulting color may then be undesirable or objectionable toconsumers.

To avoid being stirred into the mixture, vacuum pressure may be appliedduring the mixing process. This requires an extensive set up includingthe vacuum itself and seals to maintain the pressure. The vacuum systemand seals require maintenance, and occasionally leak which results indowngraded product.

While such mixers have been used commercially for many years, they havesignificant drawbacks. For example, one of the problems is that air mayundesirably be drawn into the product. Other drawbacks for the mixersinclude their space requirements and cost due to their large size, laborcosts, the length of time required for processing each batch, vathandling and transfer yield loss, and the time and expense associatedwith cleaning of the apparatus.

In addition to the problems encountered with batch mixers for both wholemuscle products and emulsified products, there are additionalconstraints for mixers that process whole muscle products. For example,in reducing the time required for processing and accelerating theformation of a stable meat mixture, the meat chunks introduced into themixer may be subject to increased shear forces. However, high shearforces may not only distort the shape of size of the meat pieces butalso impact the texture, mouth feel, and appearance of the meat afterprocessing. Thus, in an effort to speed-up the processing of whole meatproducts, the processes cannot subject the whole meat to excessive shearforce.

SUMMARY

The illustrated method and apparatus comprise improved methods andapparatus for use in making processed meat products including wholemuscle meat products by providing significant advantages with respect tothe size of the apparatus, the time required for processing, the controlof the process, and/or other aspects of the manufacturing process.

In one embodiment, the method and apparatus provides for makingprocessed whole muscle meat product in a meat mixer with a housinghaving an input and an output a distance away. The housing having a pairof parallel rotating shafts with mixing elements located thereon. Aplurality of constituents including whole muscle meat and salt solutionare input into the meat mixer for processing. By one approach, one ofthe mixing elements has a generally frustoconical shaped body. Thefrustoconical mixing element may have a generally circular cross sectionof increasing diameter or a generally circular cross section withdecreasing diameter. In another example, the frustoconical mixingelement includes both, a section with an increasing diameter and asection with a decreasing diameter. The frustoconical mixing element maybe employed in a working zone to increase diffusion of the salt solutioninto the whole muscle meat and otherwise assist with processing of themeat. By another approach, one of the mixing elements has a generallyellipsoidal-shaped body. A mixing element with the generally ellipsoidalsurface may be employed in a massaging zone to increase diffusion of thesalt solution and otherwise assist with processing of the meat. By yetanother approach, one of the mixing elements impedes the flow of theplurality of constituents within the meat mixer. A mixing element with ablocking configuration may impede the flow of the constituents toincrease the work done on the constituents at a point upstream of theblocking mixing element.

BRIEF DESCRIPTION OF THE DRAWINGS

The above needs are at least partially met through provision of theMethod and Apparatus for Meat Processing With Expansion and CompressionElements described in the following detailed description, particularlywhen studied in conjunction with the drawings, wherein:

FIG. 1 comprises a schematic representation of a continuous mixingprocessor as configured in accordance with various embodiments of theinvention;

FIG. 2 comprises a perspective view of a mixing apparatus as configuredin accordance with various embodiments of the invention;

FIG. 3 comprises a front elevational view of another component of theapparatus of FIG. 2 as configured in accordance with various embodimentsof the invention;

FIG. 4 comprises a front elevational view of another component of theapparatus of FIG. 2 as configured in accordance with various embodimentsof the invention;

FIG. 5 comprises a front elevational view of another component of theapparatus of FIG. 2 as configured in accordance with various embodimentsof the invention;

FIG. 6 comprises a fragmentary side view of a segment of a rotationalelement as configured in accordance with various embodiments of theinvention;

FIG. 7 comprises a flow diagram representing a process as configured inaccordance with various embodiments of the invention;

FIG. 8 comprises a flow diagram representing a process as configured inaccordance with various embodiments of the invention;

FIG. 9 comprises a magnified image of a piece of meat showing muscleprotein striation;

FIG. 10 comprises a magnified image of a piece of meat after a highshear processing step;

FIG. 11 comprises a magnified image of a piece of meat after a curingstep in the presence of a salt solution

FIG. 12 comprises a magnified image showing a piece of meat after thehigh shear processing step in the presence of salt solution;

FIG. 13 comprises a table listing configurations of rotational elementsfor the apparatus as described herein and data relevant thereto;

FIG. 14 comprises a graphical representation of a measure of emulsionstability for the configurations of FIG. 13;

FIG. 15 to 20 comprise schematic representations of the configurationsof FIG. 13;

FIG. 21 comprises a geographical coordinate representation showingorientations of components within the apparatus;

FIG. 22A to 22D comprise various views of an element of the mixingapparatus as configured in accordance with various embodiments of theinvention;

FIG. 23A to 23C comprise various views of an element of the mixingapparatus as configured in accordance with various embodiments of theinvention;

FIG. 24A to 24D comprise various views of an element of the mixingapparatus as configured in accordance with various embodiments of theinvention;

FIG. 25A comprises perspective view of a mixing apparatus as configuredin accordance with various embodiments of the invention;

FIG. 25B comprises schematic representation of the configuration of FIG.25A;

FIG. 26A comprises perspective view of a mixing apparatus as configuredin accordance with various embodiments of the invention;

FIG. 26B comprises schematic representation of the configuration of FIG.26A;

FIG. 27A comprises perspective view of a mixing apparatus as configuredin accordance with various embodiments of the invention;

FIG. 27B comprises schematic representation of the configuration of FIG.27A;

FIG. 28A comprises perspective view of a mixing apparatus as configuredin accordance with various embodiments of the invention;

FIG. 28B comprises schematic representation of the configuration of FIG.28A;

FIG. 29 comprises a table illustrating results from mixing elementconfiguration as configured in accordance with various embodiments ofthe invention; and

FIG. 30 comprises a graphical representation of meat piece sizedistribution.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions and/or relative positioningof some of the elements in the figures may be exaggerated relative toother elements to help to improve understanding of various embodimentsof the present invention. Also, common but well-understood elements thatare useful or necessary in a commercially feasible embodiment are oftennot depicted in order to facilitate a less obstructed view of thesevarious embodiments of the present invention. It will further beappreciated that certain actions and/or steps may be described ordepicted in a particular order of occurrence while those skilled in theart will understand that such specificity with respect to sequence isnot actually required. It will also be understood that the terms andexpressions used herein have the ordinary technical meaning as isaccorded to such terms and expressions by persons skilled in thetechnical field as set forth above except where different specificmeanings have otherwise been set forth herein.

DETAILED DESCRIPTION

Generally speaking, pursuant to these various embodiments, a continuousmethod and system for processing whole muscle meat is illustrated inFIG. 1 and FIGS. 22A through 28B. The system for continuous productionof a whole muscle meat product includes a housing, such as housing 20,having a pair of parallel rotating shafts 19 with a plurality of mixingelements 18, such a frustoconical elements 18 d, blocking element 18 e,or ellipsoid element 18 f, mounted thereon. The mixer housing 20 has aninput to receive the meat ingredients, such as whole muscle meat, a saltsolution, water, preservatives, and other additives such as spices. Themixer housing 20 also has an output, which is separated a distance fromthe input, such that the output discharges the whole muscle meat productafter the ingredients have traveled from the input to the output alongthe rotating shafts. As the whole muscle meat moves from the input tothe output, the mixing elements 18 work the meat along with the otheringredients thereby increasing ingredient incorporation includingdiffusion of the salt solution into the whole muscle meat pieces. Byworking the whole muscle meat and the ingredients with the mixingelements 18 d having a frustoconical body, the salt solution and otheringredients quickly diffuse into the whole muscle meat withoutexcessively macerating or tearing the whole muscle meat. The blockingelement 18 e when used as a mixing element 18 along the shaft 19increases the residence time of the ingredients at a portion of therotating shafts 19 just upstream from the blocking element 18 e.Increasing the residence time at that portion of the shaft, subjects theingredients to the action of the upstream mixing element for a longerperiod of time. By employing the ellipsoid element 18 f, the wholemuscle meat undergoes a moderate amount of tenderizing or massagingthereby increasing diffusion of the other ingredients such as the saltsolution or spices.

To preserve the integrity of the whole muscle meat, whole muscle meatprocessing requires slightly more gentle techniques than the high shearforces used for other meat products. While high shear processingprovides maceration and tenderization thereby increasing ingredientcontact and incorporation, such high shear forces typically disrupt thestructure of the whole muscle meat to such an extent that the integrityof the whole muscle structure is nearly completely destroyed. Thus, itis desirable to employ a moderate approach that sufficiently works thewhole muscle meat to disrupt enough of the structure to quickly providefor increased ingredient incorporation without excessively destroyingthe integrity of the whole muscle meat. Whole muscle meat that retainsits integrity retains the desired texture, mouthfeel, and coloring,among other characteristics.

To accommodate the more moderate ingredient incorporation techniques,the whole muscle pieces may require additional time to be worked ormanipulated by those mixing elements 18 delivering the working ormassaging. However, it is still desirable to accomplish the processingquickly, even though more moderate forces are used to process wholemuscle meat.

To balance the desire to quickly diffuse the salt solution into the meatand the desire for the whole muscle meat to keep its whole musclecharacteristics, a number of mixing elements 18 may be used includingthe frustoconical element 18 d, the blocking element 18 e, and theellipsoidal element 18 f. Working the whole muscle meat and otheringredients with mixing elements 18 having a frustoconical body diffusesthe other ingredients into the whole muscle meat without excessivelymacerating or tearing the whole muscle meat thereby retaining theintegrity of the meat. The frustoconical mixing element 18 d does nothave sharp cutting surfaces that would slice or cut the meat. A processemploying the frustoconical mixing elements 18 d works and gentlytenderizes the whole muscle meat, thereby increasing ingredientincorporation without significant particle size reduction of the wholemuscle meat pieces.

To provide additional dwell time for the ingredient to undergoadditional processing in the mixer housing, the blocking mixing element18 e may be employed. As mentioned, due to the more moderate forces,additional working or manipulation time may be needed to providesufficient ingredient incorporation. The blocking element 18 e, workswith surrounding elements to slow the flow of the ingredients and toallow the mixing elements upstream from the blocking element 18 e tohave a slightly longer exposure to the ingredients.

In one illustrative example, massaging the whole muscle meat and theingredients with ellipsoidal mixing elements 18 f stimulates ingredientincorporation without subjecting the whole muscle meat to excessiveshear forces that may bruise, tear, abrade or mince the whole musclemeat. As discussed above, while high shear processing providesmaceration and tenderization that increases ingredient incorporation,the same high shear forces also may greatly disrupt the structure of thewhole muscle meat to an extent that the integrity of the whole musclestructure is nearly completely destroyed. By employing an ellipsoidelement 18 f, the whole muscle meat may be massaged or worked toincrease ingredient incorporation without excessive damage to the wholemuscle meat pieces. The ellipsoid elements 18 f do not have edges thatcan cut or slice the meat pieces and therefore can massage or gentlypound the meat without negatively affecting the integrity of the wholemuscle meat.

In addition to the ability of the system having capabilities of workingthe whole muscle meat, the system is flexible such that alternativeelements 18 may be positioned on the twin shafts 16 to provide fordifferent processing characteristics. By one approach, some of themixing elements 18 used along the shaft 19 have sharper edges. Byanother approach, input lines may introduce ingredients into the housingmixer at slower or faster rates to alter dwell time or mixer-residencetime. This flexibility lets the user alter the processing depending onthe desired final meat product.

These and other benefits may become clearer upon making a thoroughreview and study of the following detailed description. Referring now tothe drawings, and in particular to FIG. 1, an illustrative apparatusthat is compatible with many of these teachings will now be presented.The apparatus, shown diagrammatically at 10, is capable of makingprocessed meat products as outlined herein. The illustrated apparatuscomprises a motor 12 and a belt drive 14 transmitting power to one ormore mixing devices 16 located in a housing 20. Ingredients such aschunks or pieces of meat, one or more salt solutions, water, flavoringssuch as spices, and preservatives are input through input lines,including pumps 84 directly into the housing 20. The input line pumps 84and mixing devices advance the mixture through the housing while themixing device applies a high shear rate, in one embodiment, to themixture to achieve rapid protein extraction from the meat components.The mixing devices, in one example, are made of stainless steel oranother material that is wear resistant and suitable for contact withfood product components.

While a single elongated screw as shown in FIG. 1 may be employed as amixing device in some embodiments, other embodiments employ other typesof mixing devices. The embodiment illustrated in FIG. 2 employs a twinshaft arrangement with a relatively short feed screw 17 used incombination with a longer array of mixing elements 18 on each shaft 19.

As the ingredients are forced through the housing 20, the rotatingmixing elements 18, such as the sharp-edged ovate element of FIGS. 3 and4, macerate and/or mix the ingredients. In this embodiment, theingredients are subjected to high shear force by driving them betweenthe mixing elements 18 a, 18 b, and between the mixing elements 18 a, 18b and interior walls of the housing 20. The minimum gaps or clearancesbetween the mixing elements 18 a, 18 b of one shaft 19 and the mixingelements of a second mixing device 16, as well as between the mixingelements 18 a, 18 b and the housing 20, are preferably between 0.06 in.and 0.12 in. In some embodiments, the gaps are 0.08 in. As the shaftsrotate, the distance between mixing elements 18 a, 18 b on respectiveshafts will vary so that, for instance, whole muscle portions may beforced through without being chopped or ground. Forcing the mixturethrough these gaps applies high shear force and results in rapid proteinextraction.

The meat, water, salt solution and other additives such as a spiceslurry are simultaneously fed into the mixing device. Protein extractionherein involves an intimate contact between the salt solution and thesalt-extractable proteins and breaking of the meat structure orrupturing of the membrane systems to separate protein strands, breakingthe protein strands themselves, or unraveling of the proteins. In oneembodiment, the mixing device applying the high shear force mechanicallyprovides this intimate contact, as opposed to the diffusion utilized intypical batch processes.

One mechanism for this is simply by reducing the mass transfer ordiffusion distance. By reducing the meat chunks to relatively smallpieces, the salt solution needs to diffuse only over a short distance,if at all. In other words, the work applied to the meat in the presenceof the salt or brine solution forces the salt solution into thestructure of the meat pieces. This accelerates the process, therebypromoting the necessary chemical reactions wherein chloride ions orother ions occupy bonding sites of the protein strands.

Furthermore, to the degree that the protein strands remain intact, theprocess deforms the meat chunks, which promotes unraveling of theprotein strands. FIG. 9 shows a representative unprocessed piece of meatunder magnification. As can be seen, the meat shows a regular pattern ofmuscle protein striation, the high-density regions of protein beingdarker. The inset of FIG. 9 depicts a portion of the meat piece undergreater magnification such that the high-protein regions can be seendistinctly separated by regions of low-protein density, or othermaterial such as fat.

By applying shear force to a meat piece to deform or grind the meat, theprotein strands are also deformed, flattened, stretched, and twisted.This opens up the protein structure, making them more porous, andpromotes penetration of the ingredients, including the brine solution.As the dispersion is more thorough, uniform diffusion of the saltsolution and other ingredients and additives, for instance, issignificantly increased by use of the high shear force. Referring now toFIG. 10, a representative piece of meat that has been processed with anapparatus as described herein in the absence of other constituents oringredients is shown. While still showing a regular pattern ofstriation, the meat piece has much smaller dark, high-protein-densityregions, and much wider areas of lighter color. In addition, thestriation pattern and the dark and light regions are less distinct,displaying a somewhat broken structure. In comparison with FIG. 9, it isclear that the application of shear force has opened up and made moreporous the meat piece. Accordingly, the meat piece is more acceptable ofor susceptible to diffusion of other ingredients thereinto.

This process causing rapid diffusion through the application of highshear force eliminates the need for curing, as has been described as thetime for the salt solution to diffuse through the meat chunks. Becauseof the need for curing, typical processing methods are necessarilybatch-oriented. That is, processing of certain meat products requiresdiffusion of salt solution into the meat for protein extraction tooccur. After mixing or injection with salt solution, typical processesrequire a cure or diffusion time for the large meat chunks, during whichtime the meat is set aside to allow satisfactory diffusion. The curingstage required a significant backlog or meat inventory within the plant,which is eliminated to allow for just-in-time product usage and receipt,and reduced storage needs in the processing plant.

A representative piece of meat that has undergone a static batch processcuring period is shown in FIG. 11. The piece of meat was injected inconventional manner for batch processing with a solution of sodiumchloride (NaCl) and allowed to cure for a sufficient period typical forthe meat type. By comparing the meat piece of FIG. 11 to those of FIGS.9 and 10, the cured piece of meat shows a striation pattern and colorssimilar to that of FIG. 10 wherein the dark regions are reduced in sizefrom the unprocessed piece of meat of FIG. 9, and the light regionsshowing opened or unraveled protein with ingredients diffused thereinto.

Through the application of high shear force in the presence of a saltsolution, a meat piece displays a physical structure combining both thecuring and the unraveling of the protein strands. FIG. 12 shows a meatpiece is shown that has been processed with the apparatus in thepresence of a sodium chloride solution. As can be seen, the patterns andcolors are further distorted, indicating the unraveling and porosity ofthe protein strands, as well as the infusion and diffusion of theingredients into and between the protein strands.

The apparatus 10 is capable of working meat ingredients and extractingprotein therefrom much faster than prior art batch processes.Specifically, the processing time in one embodiment is reduced from acommon 30-60 minutes to approximately 10-60 seconds and, preferably,10-45 seconds. In general, this time period is related to the throughputrate. As discussed herein, the throughput rate is mostly dependent onthe speed of pumps forcing the constituents or ingredients into themixer.

Additionally, the mixing apparatus need not be used in conjunction witha vacuum environment. Though vacuum may be applied to the mixer, cookedfinal product made with constituents processed without an applied vacuumon the mixer does not display the visible air characteristics describedabove for meat that has been churned in a typical mixing vat, nor doesit expand when cooked due to entrapped air. By one approach, during use,the interior of the mixer is generally filled with solid and liquidconstituents, and is substantially devoid of air. Little or no air isforced into the constituents. Little or no air that may be present inthe mixer is mixed in with the constituents because the mixture is notwhipped, and because the mixing time is short. By eliminating the vacuumsystem for the mixer, the process may be simplified, equipment iseliminated with a concomitant cost savings, maintenance costs may bereduced, and product loss may be reduced. It should be noted that otherprocessing steps, such as casing stuffing, may advantageously utilize avacuum system.

Through the effective use of high shear force applied over a small areaor volume of meat, a stable protein matrix is produced. Proteinextraction is rapid and easily controlled, and the protein binds themixed water and fat molecules. The protein is then able to bind with thewater and fat to form a protein/water/fat matrix. The other additivesmay be bound, in suspension, or dissolved therein. This effectivelyreduces fat and water loss to either an irrelevant level or at least toan acceptable level. Thus, the mixing device and other apparatus do notsuffer from fat being left in the equipment. The composition of thefinal product is more easily controlled without significant fat or waterbeing lost. The texture of the final product is desirable. Testingmethods, such as the Ronge Method utilizing a centrifuge to measurequantities of fat escaping from the mixture, will show that thestability of a mixture made by this method is equal to or exceeds thestability of conventional batch processed mixtures.

This system also controls protein matrix formation in emulsifiedproducts referred to as fat-free products having 1% or less fat, anexample being bologna. These products are typically a meat/additiveblend with water. In typical formulation, the blend lacks the fat whichotherwise tends to break up the protein matrix. Proteins are able toform strong gel-like structures with long, cross-linked protein strandsforming a large matrix, as has been mentioned. This results in a rubberytexture that is undesirable to consumers who expect a texture similar tothat of full fat meat products.

Typically, this protein matrix problem in the fat-free products is dealtwith by addition or selection of ingredients, though so-called fillersare generally not permitted. One method for breaking up the matrixformation is to add inert additives such as starch or non-functionalproteins for instance. Though water binds with the protein to retardmatrix formation, excessive water results in a soft product that doesnot hold together well, and that may allow excessive amounts of water toleech out. Furthermore, water may be driven off during the cook andpost-cook stages.

Fat-free products, it is believed, suffer from this problem largelybecause of the mixing times of conventional batch processes. It isbelieved that batch processing requires such extensive mixing times thatprotein linking is able to occur, and the matrix structures begin toform during this time. Analysis of final cooked product using thepresent method and apparatus has demonstrated that there is a markeddisruption in the matrix structure. It is further believed that the highshear of the present method and apparatus prevents or interferes withthe ability of the proteins to link as such, and/or the stark reductionin mixing time of the present method and apparatus reduces or eliminatesthe ability for the proteins to form these long matrix links. In anyevent, bologna and other so-called no-fat or fat-free products producedusing this method do not require any inert additives to reduce or avoidthe large matrix formation while still producing a product with thedesired texture characteristics of a full fat meat product.

For whole muscle and coarse ground products, another benefit of thepresent apparatus and method is the elimination of the commonly-knownvisible protein exudate that forms on the surface of the meats. Morespecifically, in certain batch processors, a combination of protein,salt solution, and water forms protein exudate, a sticky and viscousmaterial, as the meats sit in the curing vat for the batch processing.This must be broken up prior to further processing steps, such asdelivering through pumps. Because the present system utilizes continuousprocessing, this exudate does not have the opportunity to form.

It is believed that the protein exudate results from lengthy mixing timeperiods. That is, as a time period must elapse for the entirety of theconstituents to have sufficient protein extraction, some portions of theconstituents will allow excess protein to be extracted. By reducing andcontrolling the amount of protein extraction throughout theconstituents, the exudate is reduced or eliminated. As the mixturedischarged from the mixer is delivered relatively quickly to furtherprocessing, such as casing stuffing or thermal processing, the mixturedoes not continue to cure and extract additional proteins. In otherwords, the residence time within the mixer is less than is required forthe formation of a visible protein exudate to form, and the proteinextraction substantially ceases once discharged from the mixer. Thoughit has been suggested that the exudate is actually responsible forbonding of the meat product, elimination of the exudate has shown nodeleterious effect on the final product created as described herein.

In some cases, it may be desirable to control the temperature of themixer housing. For instance, it is believed that cooling the mixerhousing is beneficial in forming coarse ground items. It is alsobelieved that the internal temperature of the mixture during the mixingprocess optimally remains below a threshold level, or a maximum rise ininternal temperature during processing. As it has been found thatincreased shear work in the mixer improves mixture stability, reducingthe temperature of the mixture by cooling the mixer housing or inputtingingredients (such as cool water) at points along the length of the mixermay allow the residence time to increase, or allow the RPMs of themixing elements to increase. More specifically, cooling the mixture mayallow increased shear work while maintaining the temperature of themixture below the threshold level.

It should be noted that varying the size of the outlet, in the form of adischarge gate opening, necessarily affects residence time for themixture within the mixer. The opening may be in the range of ⅛ inch totwo inches.

One example of a commercially available mixer such as that described isa Twin Shaft Continuous Processor manufactured by Readco Manufacturing,Inc., of York, Pa., having 5″ diameter mixing elements 18 a oncounterrotating shafts 19, and throughput of about 6,000 lbs./hr. atabout 200 rpm. In operation, the shafts may have adjustable speeds.Satisfactory operation of the system may be achieved with rotationalvelocities of, e.g., 100-600 RPM. For the present system, the rate ofrotation determines the amount of work, including shearing, applied tothe mixture. To drive the mixture through, the mixing elements 18 and/orthe system pumps for inputting the constituents may be used. It shouldbe noted that any pumping force is not what would be termed “highpressure” such that the structural integrity of the pumps, pipes, andother components are generally not in danger of failure. The pressuredoes not force the fat to separate from the mixture. In otherembodiments, larger or smaller mixers may be used, e.g., 8 in. diametermixers having throughput of at least 20,000 lbs/hr, and up to about25,000 lbs./hr. The output may vary depending on the downstreamprocesses, such as casing or form stuffing or cooking. Typically, thethermal processes of cooking or chilling determine the actual mixingdevice output rate than can be handled downstream.

As shown in FIGS. 2-5, each of the illustrated mixing elements 18 has abore 200 through which a shaft may pass. To couple each mixing elementto the shaft for rotation therewith, each mixing element has anoncircular bore therethrough and the shaft has a cross section of thesame shape. In the illustrated embodiment, each mixing element has agenerally square bore, and the shaft accordingly has a square crosssection. More specifically, mixing element 18 a (FIG. 3) has a squarehole where two corners of the square are aligned with the points of themixing element 18 a itself. In contrast, mixing element 18 b (FIG. 4)has a square hole where two sides are aligned with the mixing elementpoints. The mixing element 18 a is referred to as a “diamond” mixingelement, while the mixing element 18 b is referred to as a “square”mixing element. Thus, the bore in one mixing element may be rotated 45degrees from a second mixing element that is otherwise identical.

As can be seen in FIG. 21, the mixing elements 18 can thus be orientedaround the shaft with essentially four different initial positions ororientations when viewed from the output end of the mixer. A firstorientation aligns the points of the mixing element through thevertically aligned positions labeled as “1.” A second orientation alignsthe points with the positions labeled “2,” 45 degrees counter-clockwisefrom the first orientation, while the forth orientation aligns thepoints with the positions labeled “4,” 45 degrees clockwise from thefirst orientation. The third orientation aligns the points throughgenerally horizontal positions labeled as “3.” However, it should benoted that the initial positions of the elements on the shaft may varyinfinitely as desired around the axis of the shaft.

As described, the mixing elements may be placed in different rotationalorientations and different orders, i.e., configurations to vary shearrate, throughput rate, and/or other process parameters. The mixingelements may also be interchanged with mixing elements of differentconfigurations as discussed in more detail below. In other embodiments,to facilitate cleaning and sterilization of the apparatus, the mixingelements may be formed integrally with the shaft as a one-piece, unitaryrotor, or may be otherwise supported for rotation therewith.

In one illustrated embodiments, mixing element 18 a (FIG. 3) and mixingelement 18 b (FIG. 4) have a generally sharp-edged ovate profile shapedsimilar to that of an American football, with a point or very smallradius of curvature at each end. The illustrated mixing elements 18 a,18 b have flat, parallel faces 206 and arcuate peripheral edge surfaces204. As illustrated in FIG. 3, the mixing elements 18 a have the edgesurface 204 perpendicular to the faces. For the mixing elements 18 b,sometimes referred to as a helical element, illustrated in FIG. 4, theedge surface 204 is angled relative to the faces. The faces of element18 b are angularly offset slightly relative to each other, so thatrotation of the mixing elements provides a forward or reverse motion inpumping the mixture through the housing 20. One or more of the mixingelements 18 b may be provided to assist the screws 17 in pumping themixture forward through the housing. Alternatively, one or more of themixing elements 18 b may be reversed so as to urge the mixture rearward.This may create regions of increased flow resistance or reverse flow sothat the dwell or mix time for the mixture or for particular portions ofthe mixture is increased, and the work imparted by the mixing device isincreased. Another mixing element 18 c is illustrated in FIG. 5. Thismixing element 18 c has a generally circular or disc-like shape. Themixing elements 18 a and 18 b may have a width of ½ inch to 1 inch, andthe mixing element 18 c may have a width of 1 to 2 inches. Spacers mayalso be placed between each element. Additional mixing elements 18 arediscussed further below.

On each shaft 19, each of the mixing elements 18 has a wiping actionrelative to one or more mixing elements on the opposite shaft to avoidbuild up of ingredients on the mixing elements by one approach. Thisself-cleaning characteristic helps to maintain flow of the ingredientsthrough the mixer, and helps in maintaining good distribution of theingredients. Shaft 19 is preferably a one piece unitary item that may beremoved from the housing 20.

A modified screw element 30 that may be used in conjunction with orinstead of one or both of the screw elements 17 and mixing elements 18is shown in FIG. 6. The screw element 30 has a helical outer edge 34disposed at a predetermined radius from the axis of the screw, andspaced from the interior of the housing by a narrow gap of, e.g., about0.08 in. On the face 32 of the screw are provided a plurality ofsharp-edged protrusions or blocks 40 for puncturing whole muscle meatcomponents of the mixture to facilitate protein extraction. Each of theillustrated protrusions 40 has five exposed faces. Each of theillustrated protrusions comprises two pair of generally parallelquadrilateral side faces 41 and a quadrilateral end face 43. The endfaces are rectangular, and in particular, square, and are perpendicularto the side faces. The end faces and side faces are substantiallyplanar.

The arrangement of the mixing elements may be constructed in differentmanners for different amounts of dwell time, as well as for differentamounts and types of work to be applied. For instance, an initialsection may be spiral fluted or screw elements which may also be usedfor pumping through the housing and which may be used for initial sizereduction of the incoming meat chunks. As the mixture passes through themixing elements 18, a first group of mixing elements may be arranged toprovide a first level of shear force application that is primarily formixing or for allowing the described reactions to occur between theprotein and salt solution, as examples. Then, the mixture may passthrough a second group of mixing elements imparting a second, higherlevel of shear force application for the purposes described herein.There may be a further grouping for applying a shear force lower thanthe second level for additional mixing, followed by a final group ofmixing elements for final high shear application, such as for final sizereduction or comminution.

The utilization of the mixing device in this manner allows forcontinuous processing, as the mixture forms a stable mixture that isoutput at one end as new material to be processed enters at the input.Pre-input hoppers including one or more grinders may be used for feedingthe meat input lines and for some amount of meat chunk size reduction tofacilitate the pumping of the meat into the mixing device. In thismanner, meats and other constituents may be simultaneously fed into acontinuous processor so that size reduction, mixing, grinding, proteinextraction, and/or emulsification may all occur continuously and in asingle piece of equipment. Thus, the amount of equipment is reduced, thefloor space required for that equipment is reduced, sanitation issimplified for the equipment, and the opportunity for contamination ofthe mixture is reduced.

The configuration of the rotating mixing elements such as the mixingelements may be adjusted depending on the type of product being mixed orbeing produced. For instance, finely chopped products resulting in asmooth and fine batter, such as bologna, may be produced. More coarselychopped products such as salami may also be produced. In addition, wholemuscle products such as turkey or ham may be processed as discussedbelow.

FIGS. 15-20 show a series of configurations for arranged elements onshafts within the mixer housing 20. In FIG. 15, a mixer 200 is depictedhaving infeed screws FS arranged at an input end 202 of the mixer 200and providing a mixing zone. Along a first shaft two series of mixingelements F, discussed earlier as flat mixing elements 18 a, and mixingelements H, discussed earlier as helical mixing elements 18 b, arearranged for providing a shear application zone. A second shaft (notshown) would be positioned parallel to the first shaft and carry screwsFS and mixing elements H, F, the selection of which corresponds to thoseon the first shaft. As depicted, the mixing elements H and F areprovided a first number 5-28 to indicate their position in the series,and the orientation of each mixing element H, F is designated by asecond number corresponding to relative positions shown in FIG. 21. Asshown, liquid injection ports may be provided along the length of themixer for providing liquid streams therein. As discussed above, theinfeed screws FS are primarily low-shear elements for forcing theconstituents through the mixer 200, while the mixing elements H, F arehigh-shear elements for applying work to constituents within the mixer200. In this configuration, each shaft has six feed screws FS, elevenhelical mixing elements H, and twelve flat mixing elements F. A reversehelical mixing element RH is provided proximate the outlet to force themixture away from an outlet wall 204 proximate a mixer outlet 206.

FIG. 16 shows a mixer 300 similar to that of the mixer 200. However, themixer 300 shows a second series of screws FS downstream from a series ofscrews FS at an input end 302. In this manner, the mixer 300 providestwo mixing zones corresponding to the screws FS, and provides two shearapplication zones. In addition, this configuration provides each shaftwith six feed screws FS, ten helical mixing elements H, and thirteenflat mixing elements F. The helical mixing elements H promote themovement of the mixture through the mixer 300, as discussed above. Byreducing the number of helical mixing elements H in the mixer 300 incomparison to the number in the mixer 200, the shear force applied inthe configuration of mixer 300 is higher.

FIG. 17 shows a mixer 400 having two mixing zones, provided by the feedscrews FS, and two shear application zones. The mixer 400 includes eighthelical mixing elements H, and fifteen flat mixing elements F. Again,with a reduction in the number of helical mixing elements H incomparison to the mixers 200 and 300, the shear force applied in thisconfiguration is increased.

FIG. 18 shows a mixer 500 having a single mixing zone proximate theinlet 502, while the rest of the mixer applies shear force. In thisconfiguration, elements numbered 4-6 and 9-11 are paired half-sized flatmixing elements F, where each of the pair is rotated 45 degrees fromthose mixing elements immediately adjacent thereto. This series allowsmore work, and thus more shear force, to be imparted to the mixture asit moves through such a region. Furthermore, three additional reversehelical mixing elements RH are provided. As the helical mixing elementsH promote the mixture moving through the mixer, the reverse helicalmixing elements RH retard this movement and provide a backward force tothe mixture. This action alone increases the work applied in comparisonto flat or helical mixing elements, but also increases residence time,thereby further increasing the applied work and shear force applied tothe mixture. The number of feed screws FS is reduced to four, therebyallowing more high-shear elements to be placed on the shaft. Thisconfiguration utilizes only three helical mixing elements H, and 15 flatmixing elements F, in addition to the half-sized mixing elements andreverse helical mixing elements RH.

An even greater amount of shear force application is achieved with theconfiguration of FIG. 19. A mixer 600 is provided similar to that of themixer 500. However, a blister ring BR is provided, discussed earlier asmixing element 18 c. In order to accommodate the blister ring BR, thereare only fourteen flat mixing elements F and two helical mixing elementsH. The blister ring BR applies more shear than any of the helical, flat,or reverse helical mixing elements. To achieve this, the blister forcesthe mixture through an annular space and this annular space is anarrowed pathway through which the mixture passes.

FIG. 20 shows an even higher level of shear force application. For amixer 700 depicted in FIG. 20, the helical mixing elements H have beenremoved, and a total of 4 reverse helical elements are provided. Incomparison to each of the previous configurations depicted in FIGS.15-19, the mixer 700 provides an even greater amount of shear force andwork to the mixture.

Testing was performed to determine emulsion stability of variousmixtures utilizing a product formula for beef franks. When the mixtureleaves the mixer, whether batch processor or an apparatus as describedherein, the mixture will be processed by other machinery and forces.Accordingly, the mixture must not lose stability during this downstreamprocessing. As noted above, a stable emulsion is consider as being onethat loses less than 2% of the final product due to fat cook-out duringcooking. With reference to the table of FIG. 13, test results for anumber of conditions corresponding to the configurations of FIGS. 15-20are presented, and conditions 5 and 16 represent control batches madefrom a conventional batch mixing system. The testing was done such thatmixture produced from each condition was placed in a separate piece ofmachinery that applied a shear force many times greater than the shearforce of the apparatus as described herein. After every minute of theadditional shear being applied, a sample was removed and cooked.

It is generally considered that an emulsion is sufficiently stable ifthree minutes of additional shear do not result in the emulsion havingcookout greater than 2% of the product, by weight, lost due to fatcook-out. The testing determined that the control mixtures withstoodadditional shear force for approximately 6-8 minutes before theadditional work resulted in excessive fat and water cookout, and wasunstable at greater time periods. As can be seen in FIG. 13, each of theother conditions resulted in a mixture that withstood at least threeminutes of additional shear force application. For the mixers 500, 600and 700, the emulsion stability was comparable or better than theemulsion stability of the batch processed mixture. The point at whichthe additional shear force application causes the emulsion to losestability is referred to as Time to Break, and the results of thistesting are presented graphically in FIG. 14 to show the Time to Breakfor each condition. It should also be noted that no significantdifferences were noted in the final appearance for the cooked productresulting from each condition.

The ingredients are preferably pumped through the input lines into themixer, though an inlet hopper 62 may alternatively also be employed, asis shown in FIG. 1. As noted earlier, pre-input hoppers 68 may beprovided as storage into which plant personnel load a quantity ofmaterials. In addition, a grinder or pre-blending device 64 may beprovided prior to or within the hopper 62 to provide an initial mixing,grinding, or blending action, and/or to assist in pumping the inputstreams downward through the hopper.

Ingredients are supplied as input streams by a plurality of inputassemblies 66. The input streams may include a first stream comprisingpredominantly lean meat or muscle content, a second stream comprisingpredominantly fat content, a third stream comprising one or more saltsolutions such as sodium chloride dissolved in water as well as anyspices or flavorings, a fourth stream comprising an aqueous nitritesolution, and a fifth stream consisting essentially of water. Additionalingredients including flavorings such as spices, preservatives, and/orother ingredients may be introduced in additional streams, or may beincorporated in one of the five streams described above. Some meatproducts may utilize more than two meats, and in some of these instancesthe system may include additional input assemblies. In other cases, somemeat products require small amounts (relative to the overall mixture,such as in the range of 2-5%) of a plurality of particular meats, andthese may be pre-mixed and delivered to the mixer with a single inputfor metering them in at the relatively low rate. Each input line may beprovided with the hopper 68 or tank which may hold a pre-mixed quantityof its respective constituent. For instance, a relatively low rate ofnitrite solution is used, so a single, pre-mixed quantity in a vatmetered through an input line is sufficient for the continuousprocessing. A left-over-batter line may also be provided to returnbatter to the mixer for reworking.

In the embodiment of FIG. 1, each of the input assemblies 66 includes afeed line 80 for carrying an ingredient to the inlet hopper 62, acontent analyzer 82 on the feed line, and a metering pump 84 or valvedownstream from the analyzer on the feed line. In other embodiments,e.g., the embodiment of FIG. 7, content analyzers are employed on somebut not all of the input assemblies.

As an ingredient stream passes through an associated content analyzer82, the stream is analyzed to determine, for example, fat, moistureand/or protein content. In order to achieve balance between the variousingredients in the desired ratio, a control system receives input from aplurality of analyzers, and regulates the throughput rates of themetering pumps 84 so that the ingredients flow into the inlet hopper 62in the desired ratio, as specified by the product formula.

Various methods may be used for analyzing the fat, moisture, and proteincontent. Known methods include use of microwave energy or infraredlight. Commercially available in-line analyzers may be programmed toanalyze characteristics of a wide variety of substances ranging from,e.g., petrochemicals to processed cheese. Examples of such analyzersinclude in-line analyzers GMS#44 and GMS#46 manufactured by Weiler andCompany, Inc., of Whitewater, Wis., and the Process Quantifiermanufactured by ESE Inc. of Marshfield, Wis. These analyzers typicallymust be calibrated for each individual application, either by themanufacturer or by the end user.

FIG. 7 illustrates a process embodying the invention comprising acontrol system 100 balancing flow rates of a plurality of input streamsto maintain compositional parameters within desired ranges using a feedforward analysis. In the process of FIG. 7, there are two meat inputstreams 102 and 104. In other embodiments, the process may employ onlyone meat input stream, or three or more meat input streams.

The process preferably employs one or more additional input streams tosupply moisture, flavor enhancers, preservatives, and/or otheringredients. In the process of FIG. 7, there are three non-meat inputstreams comprising a spice/water blend input stream 106, a water inputstream 107, and an aqueous nitrite solution input stream 109. Otherembodiments may employ more or fewer non-meat input streams.

To produce a mixture with desired moisture, protein and fat contentlevels, the control system 100 regulates the flow rates of the inputstreams by adjusting the speed of a pump or valve associated with eachinput stream. In the embodiment of FIG. 6, metering pumps 110 and 112regulate flow rates of the meat blend input streams, and additionalpumps or valves 114, 115 and 117 are employed to regulate the flow ratesof the other input streams.

Adjustments are made using a feed-forward method whereby the pumps andvalves provide the proper relative amounts of the input streams based onupstream analysis. To determine the need for adjustments to the variousflow rates, the control system 100 utilizes the content analyzers 82 todetermine the protein, fat and/or moisture content levels of ingredientinput streams 102, 104 upstream of the metering pumps 110 and 112. Insome embodiments, for each input stream element that is analyzed,analysis is completed before the element reaches the metering pumpassociated with the input stream so that the flow rate of the associatedinput stream may be adjusted as needed to maintain the desiredcompositional parameters of the combined output stream continuouslywithin the target range. In other embodiments, analysis may take placeafter the element has passed through the metering pump, and flow ratesmay be adjusted as necessary to account for the delay. Thus, thepercentages of protein, moisture and fat entering the mixer arepreferably regulated so that adjustments to variations in input streamcharacteristics are made as the input streams flow into the hopper,rather than being made in response to characteristics of the mixturemeasured downstream from the mixer 10.

More specifically, the control system 100 initially receives aprescribed formulation for the meat product, such as from a database.The control system 100 then receives information regarding thecomposition (i.e., fat content, water content, etc.) of the meatspassing through the analyzers. The control system solves a set of massbalance simultaneous equations to determine whether the materialspassing through the analyzers are in the proper ratios for the finalmeat product. To the degree that the materials are outside of ashort-time-period average balance, the control system 100 will adjustthe speed of one or more pumps to hold the mass balance within atolerable range. These equations may be the same equations that wouldotherwise be solved by plant personnel in order to adjust the inputmaterials based on the batch sheet, discussed above. By providing thecontrol system 100 with standard known parameters for a mixture thatwill produce the desired final meat product, the control system 100 canautomatically, continuously, and dynamically adjust the mixture so thatthe output is consistent and properly balanced. As also notedpreviously, in typical batch systems, the only sampling that can be doneis from the mixing vat, at which point it is difficult and tedious toadjust the balances. The control system 100 and mixing device allow fora composition controlled mixture to be consistently and uniformlyproduced, and the tighter composition control may result in increasedproduct yields and improved product quality.

By one approach, the mixer 10 includes an output port 122 fordischarging the mixture, and may include an outlet hopper 124 to receivethe mixture and channel it to a delivery pump 126. If it is desired tomaintain the process at subatmospheric pressure, one or more vacuumlines may be in communication with the apparatus in one or more points.FIG. 1 illustrates a vacuum line 120 in communication with the inlethopper 62. In other embodiments, vacuum lines may be connected to otherlocations in addition to or instead of the inlet hopper. For example,vacuum lines may be connected to the outlet hopper, to points betweenthe inlet and outlet hoppers, and to points downstream from the outlethopper.

As the protein extraction is a function of time and shear force in thepresence of a salt solution, the power drive 12 may be a variable speedmotor so that the constituents are contained within the housing 20 formixing for a time necessary to allow both salt solution infusion andshearing action.

In connection with sensing fat, moisture and protein content of meatcomponents, it has been found that moisture content may correlate to fatand protein content. It is believed that the correlation may besufficient to enable moisture content of meat components from a knownsource to be used as a predictor of fat and/or protein content withsufficient accuracy that fat and/or protein content may effectively bemeasured simply by measuring moisture content. Accordingly, in certainembodiments of the invention, the step of measuring fat and/or proteincontent may consist of measuring moisture content after havingcalibrated the moisture meter appropriately. The control system can thencontrol fat and/or protein input based on the moisture content readingsof one or more input streams.

In utilizing the system described herein, plant personnel may receive abatch sheet from a database for the formulation of a particular meatproduct. The plant personnel may then select appropriate meats forinputting into the system based on fat, protein, and/or water content.However, the precision with which they are selected need not be asaccurate, to the degree that the vendor-provided ratings may generallybe relied upon. Furthermore, the system allows the meat chunks to bedelivered directly into the pre-input hopper 68 which may or may notperform initial size reduction, thus eliminating the need for theinjection and curing stages and their accompanying vats. At this point,the control system 100 takes over the processing of the meat and otherconstituents. The control system 100 itself receives or pullsautomatically the batch sheet from the database and calculates thenecessary mass balance equations. As described, the control system 100monitors and adjusts the system including the pumps and mixing device toproduce a generally uniform composition stable protein matrix. Theoutput stream of meat product mixture from the mixing device may firstproceed to a surge hopper to take into account minor breakdowns in thesystem, and may then be easily and simply conveyed to further processingsteps, such as casing or form stuffing and cooking/thermal processes.The surge hopper fills from the bottom to the top, so there is verylittle mixing or aeration issues as a result of its use. The controlsystem analyzes the composition needs and what is present, and adjustsaccordingly. Thus, human interaction is reduced to providing theconstituents, such as by loading meat into the hoppers 68, andresponding to alarms or alerts from the system providing notice thatthere is a problem such as a constituent running out. The result is areduction in labor, more accurate and higher yields (less yield loss),greater food safety and reduced likelihood of contamination due to thesubstantially closed system and lack of transfer, reduced spacerequirements from the elimination of the vats and coolers, improvedproduct uniformity, and reduced maintenance due to the elimination ofvat and transfer traffic, as well as savings from the elimination of thevats themselves and the injection stages.

The communication between the control system 100 and the corporatedatabase is directed in both directions. That is, the control system 100may receive the batch sheet of base formula, formulation rules (such asmaximum fat content), and finished batter targets directly, as well asprovide feedback to the database regarding the actual materials used. Asthe database may have a dated or inaccurate formulation, the informationfrom the control system 100 may be uploaded to correct the formulation.In addition, the control system may provide information detailing theactual compositional rating in comparison with the vendor specificrating which is generally a small sample estimate. This allows ahistorical view of a specific vendor and can trend changes in meatsprovided by specific vendors. This feedback can be used by the databaseto assess materials on-hand and purchasing requirements, as well ascompare the yield results to materials usage. The data collectionenabled by this system can trend various aspects of the operation tosearch for inefficiencies and spot for improvements therein. In priorsystems, the database tends to have a static formulation, while thepresent control system allows for dynamic repositioning of thatformulation. The control system thus responds to changing materials,compensates for unavailable materials, and provides feedback forre-setting the formulation at the database.

While one approach employs breaking down the meat chunks to increasediffusion of the salt solution into the meat, in certain meat productssuch as whole-meat products, overly aggressive processing that breaksthe meat into many small meat portions may negatively affect theintegrity. Thus, it is desirable to increase diffusion of the saltsolution without excessively breaking down the structure of the meat.

Conventional batch processing of certain whole muscle meat products,such as ham, corned beef, or turkey, involves the injection of cure,brine, and ingredients followed by about 45 minutes of mixing, fortyhours of curing, and then stuffing and cooking of the cured meat. Asmentioned above, the apparatus and the continuous method disclosed maybe adapted to accommodate the processing of whole muscle meat products.Moving to a continuous process that reduces process and curing time,without negatively affecting the integrity of the final product, isdesirable. Balancing the rapidity of the process with the integrity ofthe meat product produced is important for continuous whole muscle meatprocessing. The process should facilitate efficient ingredient diffusionand incorporation while retaining the whole muscle characteristics ofthe meat.

The apparatus 10 for continuously processing meat products disclosedherein is a twin shaft arrangement with a relatively short feed screw 17used in combination with an array of mixing elements 18 on each shaft19. The mixing elements 18 that perform the mechanical mixing action maybe interchangeable. The particular mixing elements 18 employed,including their arrangement along the shaft 19, are chosen for theprocessing of whole muscle products based on their ability toefficiently process the meat without unnecessarily reducing the size ofthe muscle pieces or significantly tearing or cutting the meat pieces,as such destructive actions negatively affect the appearance and textureof the whole muscle products. Further, appearance and texture areconsidered an important factor for consumer satisfaction. As shown inFIG. 1, the ingredients may be fed into the housing 20 by hopper 62. Thehopper 62, as illustrated, may be located adjacent one end of thehousing. In another illustrative embodiment, the hopper 62 may belocated near the center of the length of the housing 20. By yet anotherapproach, the ingredients may be fed directly into the mixer throughinput lines without employing a hopper. Additional apparatus shown inFIG. 1, such as the content analyzer 82 or the pre-input hoppers 68 mayalso be used in the continuous processing of the whole muscle meat;however, it is also contemplated that the whole-muscle meat be processedwithout such additional apparatus. Further, if on-line compositionalassessment is employed in the processing of whole muscle meat, thecontrol stream may include the protein content as opposed to, or, inaddition to, water.

Turning now to FIGS. 22A through 28B, mixing elements 18 d, 18 e, and 18f are illustrated alone and in combination with other mixing elements18. The array or configuration of the rotating mixing elements 18, asmentioned, may be adjusted depending on the type of product beingprocessed. FIGS. 22A-D illustrate a mixing element 18 d having afrustoconical shape. FIGS. 23A-C illustrate a blocking mixing element 18e. FIGS. 24A-D illustrate an ellipsoid-shaped mixing element 18 f. Themixing elements 18 d, 18 e, and 18 f are well-suited for processing ofwhole muscle meat products as described below. More particularly, wholemuscle products processed as described herein show good water bindingand cook yield, somewhat similar to results produced in conventionalbatch processing but in significantly less time. In sum, the processedwhole muscle shows extensive structural disruption and changesconsistent with conventional processing without significant damage tothe meat integrity, in significantly less time.

FIG. 25A illustrates a perspective view of a portion of the apparatus 10with the top portion of the housing 20 removed. The parallel rotatingshafts 19 have mixing elements 18 positioned thereon, including thefrustoconical-shaped mixing element 18 d and the ellipsoid-shapedelements 18 f, which are discussed in detail below. The frustoconicalmixing element 18 d has a changing diameter or circumference about anaxis parallel to the opening or bore 200 d, which is similar to bore200. As previously discussed, the bore 200 that extends through themixing elements 18, including frustoconical element 18 d, isnon-circular. The shaft 19 also has a non-circular cross section suchthat once the element 18 is positioned on the shaft 19, the two partsare coupled together. The bore 200 d is sized to fit the shaft 19. Inthe example of FIG. 22B, the bore 200 d has a generally square shapewith four straight sides 129 and corners 128 that are rounded. Inanother embodiment, the bore 200 d has corners 128 that are beveled.

As shown in FIG. 22D, the single frustoconical element 18 d has a largerdiameter end face 130, a smaller diameter end face 132, and a sidesurface 134. The double frustoconical element 18 d, shown in FIG. 22A,includes two frustoconical portions having the larger diameter end faces130 abutting one another. The double frustoconical element 18 d does nothave an exposed larger diameter end face 130 but has two exposed smallerdiameter end faces 132 and an outermost side edge 136, which is thewidest section of the element 18 d. By one approach, the doublefrustoconical elements 18 d having expanding and contracting crosssections may be manufactured in a unitary configuration. Alternatively,each of the frustoconical mixing elements 18 d may be individuallymanufactured with a smaller diameter end face 132, a larger diameter endface 134, and a side surface 134 that tapers in one direction such thatthe cross section either increases or decreases in size. Theseindividual frustoconical mixing elements 18 d may be combined togetherto create a double frustoconical mixing element 18 d. To preventunnecessary damage to the meat pieces, the frustoconical elements 18 ddo not have sharp shearing surfaces.

The frustoconical mixing element 18 d, illustrated in FIGS. 22A to 22D,promotes efficient infusion of the salt solution and flavoring into themeat pieces in the continuous or inline meat processor as discussedabove. The continuous meat processing saves significant time over thegeneral batch processing. Using the frustoconical mixing element 18 d,along with other mixing elements 18, permits quick processing of wholemuscle meat in the continuous inline meat mixer. Various dimensions ofthe frustoconical mixing element 18 d are discussed below with theprototype and configuration evaluation.

The shaft 19 typically includes a variety of mixing elements 18 as shownin FIGS. 25A-28B. At the input end 65 of the housing 20, which may beconnected to the input hopper 64 and input lines or assemblies 66, thefeed screw 17 or the modified screw element 30 is positioned to advancethe ingredients in the housing 20. Opposite the input end 65, thehousing 20 has an output end 67. As the ingredients are advanced throughthe housing 20, the mixing elements 18 work the meat chunks to increaseincorporation of the salt solution, spices, and other additives into themeat chunks. The mixing elements 18 have paddle positions, such as 1, 2,3, or 4, denoted underneath the specified element in FIGS. 25B, 26B,27B, and 28B. That paddle position denotes the rotation of the element,which corresponds to the rotational positions shown in FIG. 21. By oneapproach illustrated in FIG. 25A, downstream from the feed screw 17 theshafts 19 include a plurality of ellipsoid-shaped elements 18 f(described below) to subject the meat to a massaging action and then aplurality of frustoconical mixing elements 18 d to work the ingredientsand the circular-shaped or spacer element 18 c as illustrated in FIG.22A. More particularly, in one example, the parallel shafts 19 have acircular-shaped element 18 c located downstream from theellipsoid-shaped elements 18 f followed by a frustoconical mixingelement 18 d with the smaller diameter end face 132 facing upstream andthe larger diameter end face 134 facing downstream. The larger diameterend face 134 then abuts a larger diameter end face 134 of anotherfrustoconical mixing element 18 d. Thus, the diameter of the elementsincreases and decreases, then remains steady at the circular-shapedelement 18 c and the pattern repeats as illustrated in FIG. 22A. Asdiscussed in more detail below with respect to FIG. 30, the elementconfiguration of FIG. 25A-B provides a moderate amount of ingredientincorporation while retaining the meat in large pieces. Such aconfiguration of mixing elements 18 may be desired for a number of wholemeat products.

A configuration of mixing elements may be viewed as a group offunctional, processing zones. By one approach, the shafts 19 have aningredient advancement zone, as illustrated by the feed screws 17 inFIG. 25A. Downstream from the ingredient advancement zone, theconfiguration may include a massaging zone, as illustrated by theellipsoid-shaped mixing elements 18 f in FIG. 25A. A series offrustoconical mixing elements 18 d and circular-shaped elements 18 c maybe mounted on the shafts to provide a working zone downstream from themassaging zone, as illustrated in FIG. 25A. The series of mixingelements 18 may include a repeating sequence such as a circular-shapedelement 18 c, a frustoconical mixing element 18 d with increasingdiameter, a frustoconical mixing element 18 d with decreasing diameter,(the two frustoconical mixing elements could be replaced by a doublefrustoconical mixing element), and another circular-shaped mixingelement 18 c. By viewing the elements as comprising a series ofprocessing zones, one may more easily and quickly alter the elementconfiguration to account for differences in the type of meat beingprocessed. For example, if the desired type of product requires a bitmore ingredient incorporation and the meat can handle a short period ofmoderate to high shear force, one of the processing zones or a portionthereof may be changed to include a plurality of sharp-edged ovateprofile elements 18 a, 18 b. In the illustration of FIG. 25A, themassaging zone could be exchanged for a zone having increased shear.

The parallel shafts 19 and the mixing elements 18 thereon work togethercooperatively to process the whole muscle meat. In choosing the mixingelement and its rotation in an array, the configuration on the otherparallel shaft 19 is examined. More particularly, the mixing elements 18on one of the parallel shafts typically impact and work together withthe adjacent mixing element 18 positioned on the other parallel shaft.For example, the feed screws 17 positioned at the input end 65 of bothparallel shafts 19 work together to move the ingredients forward. Withthe configuration illustrated in FIG. 25A, for the zone with theellipsoid mixing elements 18 f, the position of the ellipsoid-shapedelements 18 f on one shaft 19 is rotational offset from the position ofthe adjacent ellipsoid-shaped elements 18 f on the other shaft such thatboth elements 18 f may rotate with the shafts 19 to which they arecoupled without interfering with the adjacent element 18 f. Thus, whilethe configuration is similar, the two parallel shafts 19 do not have thesame configuration and are not mirrors of one another. In addition, themixing elements 18, such as the repeating series of elements found inFIGS. 26, may be mounted in a laterally offset arrangement from oneanother along the shafts 19 as discussed below with respect to FIGS.26A-B. However, as illustrated in FIG. 25A, the series of frustoconcialmixing elements 18 d are not offset, instead the mixing elementconfiguration on one of the shafts 19 in the frustoconical mixing zonemirrors the other shaft 19 along that same section of the shaft 19. Moreparticularly, as one shaft 19 has a frustoconical element 18 d with anincreasing diameter, the other shaft 19 also has a frustoconical element18 d with an increasing diameter. Thus, the two shafts 19 have the sameconfiguration of mixing elements 18 along one section of the shafts 19.Returning to FIG. 22A, the series of similar adjacent frustoconcialmixing elements 18 d and circular-shaped elements 18 c continues alongboth shafts 19. The simultaneous increasing and decreasing of the mixingelements 18 d increases and decreases the size of the pathway for themeat and ingredients to pass through. This creates a working action,such as by compression and expansion of the pathway, working the meatpieces and ingredients together to increase the ingredient incorporation

By working the meat with frustoconical mixing elements 18 d andcircular-shaped elements 18 c arranged in series, the meat processingproduces muscle pieces with increased ingredient incorporation,distribution and equilibrium throughout the highly organized cellularstructure of the whole muscle meat quickly. The ingredient incorporationinto the meat may occur by disrupting or rupturing the membranes of themeat while not destroying the overall integrity of the meat or fullysevering the connections within the meat. Thus, without employing highshear or creating a protein exudate, the meat mixer may quickly processwhole muscle meat. Reducing the cut-points of the mixing elements 18assists with prevention of over-working the meat product. Thefrustoconical elements 18 d do not have significant, sharp jutting edgesor “cut points” that may work the meat pieces too severely therebyexcessively tearing, bruising, shearing, abrading, macerating, orotherwise significantly damaging or changing the integrity of the meat.

Turning now to FIG. 26A, a portion of the housing 20 is illustratedshowing a pair of parallel rotating shafts 19 having mixing elements 18coupled thereto in another configuration. Similar to previousconfigurations, a pair of feed screws 17 are located at the beginning ofthe parallel shafts 19. Downstream from the feed screws 17, are aplurality of different mixing elements 18. At least some of the mixingelements 18 shown in the configuration of FIG. 26A having a blockingconfiguration. The blocking element 18 e impedes the flow of mixture orproduct constituents such that the mixture remains upstream from theblocking element 18 e for a longer period of time. More particularly,the residence time of the mixture upstream of the blocking element 18 eis increased such that the upstream mixing elements 18 have additiontime to process the mixtures.

As illustrated in FIGS. 23A-C, the blocking mixing element 18 e has flatfront and back surfaces 140 and a side surface 142 with a first U-shapedsurface 144 and a second surface 146. The second surface 146 isconfigured such that its radius of curvature generally corresponds tothe inner wall of the mixer housing. The first U-shape surface includesa pair of substantially parallel side surfaces 144 a and a generallyrounded surface 144 b. The blocking mixing elements 18 e has a bore 200;however, the bore 200 e of mixing elements 18 e is not centrallylocated. Instead, the bore 200 e is offset away from the second surface146 and toward the generally rounded surface 144 b of the first U-shapedsurface 144. As the blocking element 18 e rotates, the second surface146 follows the inner surface of the mixer housing and may rotate towithin an ⅛ inch of the interior wall. The bore 200 e shown in FIGS.23A-23C is generally square in shape having four sides 148 and roundedcorners. Two of the sides 148 of the bore 200 e are substantiallyparallel to side surfaces 144 a. However, it is contemplated that thebore 200 e may be rotated with respect to the side surface 142, such asby 45 degrees. By one approach, the blocking element 18 e has a somewhatrectangular shape with rounded edges nearest the bore 200 e, thoughother shapes are contemplated. Various dimensions of the blockingelement 18 e are discussed below with the prototype and configurationevaluation.

The bore 200 e is positioned within blocking element 18 e such that asthe blocking element 18 e is rotated by the rotation of the shaft 19,the second surface 146 extends outwardly toward the wall of the housing20. This provides minimal space for the ingredients to move past theblocking element 18 e around the second surface 146. Thus, theingredients are slowed from advancing, forced to find an alternativepathway such as around the first U-shaped surface 144 or continuingadvancement once the blocking element 19 e has rotated out of thepathway. The blocking element 18 e may temporarily prevent theingredients from proceeding downstream. By slowing the advancement ofthe meat pieces, the meat mixture remains just upstream from theblocking element 18 e for a slightly longer period of time and whichevermixing element 18 is positioned just upstream from the blocking element18 e has additional time to work the mixture. In sum, the additionalresidence of the ingredients provides more exposure to the mixingelement 18 and other conditions just upstream from the blocking element18 e. Further, if additional ingredients are desired or if thetemperature of the mixture needs altering, an inlet may be positionedjust upstream from a blocking element 18 e. Thus, the blocking elements18 e work in conjunction with the surrounding mixing elements 18 orinputs.

Several illustrative blocking elements 18 e are mounted to the shafts 19in FIGS. 26A-B. Similar to previous configurations, the housing has aninput end 65 and an output end 67. As the ingredients are advancedthrough the housing 20 from the input end 65 to the output end 67, themixing elements 18 work the ingredients including the meat pieces toincrease diffusion of the salt solution and other ingredientincorporation. By one approach illustrated in FIGS. 26A-B, a few of theblocking elements 18 e are positioned just downstream from thesharp-edged ovate mixing elements 18 a which impart a higher shear tothe meat and other ingredients. By increasing the ingredients' exposureto the higher shear elements, fewer of these elements 18 a may berequired. The blocking elements 18 e positioned on the adjacent parallelshaft 19 are shown rotated 90 degrees relative to one another such thatthe elements 18 e may rotate with shafts 19 without interference fromthe adjacent element. It is anticipated that a variety of mixingelements 18 may be positioned upstream from a blocking element. Theconfiguration of FIGS. 26A-B also illustrates a variety of frustoconicalmixing elements 18 d after a variety of elements 18 a, 18 b, 18 c, and18 e. The frustoconical mixing elements 18 d shown in FIGS. 26A-B havethe smaller diameter end face 132 facing upstream and the largerdiameter end face 134 facing downstream. The larger diameter end face134 abuts the larger diameter end face 134 of another frustoconcialmixing element 18 d, though as mentioned above, such a configuration maybe combined into a double frustoconcial mixing element 18 d. Asmentioned, the mixing elements 18 may be offset from one another alongthe shafts 19. Thus, the frustoconical mixing elements 18 d arepositioned such that a first shaft has frustoconical mixing element 18 dwith an increasing diameter and then a frustoconical mixing elements 18d with a decreasing diameter, while the second shaft has twocircular-shaped element 18 c. Then, the first shaft has twocircular-shaped elements 18 c while the second shaft has twofrustoconical mixing elements 18 d, one with an increasing and anotherwith a decreasing diameter. Such a configuration is repeated in thearrangement of FIGS. 26A-B followed by a helical sharp-edged ovateprofile 18 b, a circular-shaped element 18 c and then frustoconicalelements with an increasing diameter on both shafts 19.

As discussed above, the mixing elements can be evaluated as processingzones. For example, the configuration of FIGS. 26A-B has a zone with aplurality of sharp-edge ovate elements 18 a and helical sharp-edge ovateelements 18 b providing significant shear and then a zone havingfrustoconical elements 18 d and circular-shaped elements 18 c. Asdiscussed below, the moderate amount of shear and ingredientincorporation provided by some configurations of mixing elements 18 maybe increased slightly by adding blocking elements 18 e to theconfiguration.

Turning now to FIG. 27A, a perspective view of a portion of theapparatus 10 is illustrates two feed screws 17 and a plurality ofgenerally ellipsoid-shaped mixing elements 18 f positioned along tworotating shafts 19. The ellipsoid mixing elements 18 f located on oneshaft 19 are rotatably offset from the ellipsoid mixing elements 18 f onthe other rotating shaft 19, thus, allowing for unimpeded rotation ofboth parallel shafts 19. As shown in FIGS. 24 A-D, the ellipsoid mixingelements 18 f are generally egg-shaped and have a bore 200 f extendingtherethrough. The generally ellipsoid-shaped mixing elements 18 f havetwo rounded end points 150 and a first and second rim 152 on oppositeportions of the egg-shaped body where the bore 200 f meets the outersurfaces of the mixing element 18 f. Similar to previous mixing elements18, the bore 200 f of the ellipsoid mixing element 18 f is sized toaccept the shaft 19 and couple the ellipsoid-shaped mixing element 18 fthereto. The bore 200 f may be positioned within the ellipsoid mixingelement 18 f such that two of the beveled corners 128 are positionedoutwardly toward the rounded end points 150, as shown in FIG. 24B. Byanother approach, the bore 200 f may be rotated such that two of thestraight sides 129 may be outwardly positioned toward the rounded endpoints 150 as shown in FIG. 24C. A variety of sizes are contemplated forthe ellipsoid-shaped mixing elements 18 f as discussed below. As seen inFIGS. 24A and 24D, the base portion of the ellipsoid mixing element 18Fextends from closely adjacent one rim 152 to closely adjacent the otherrim 152.

The configuration of mixing elements 18 shown in FIGS. 27A-B includes aplurality of ellipsoid mixing elements 18 f followed by a spacer mixingelement 18 c and then an increasing diameter frustoconical mixingelement having the larger diameter face 134 facing downstream, towardthe output end 67. The plurality of ellipsoid mixing elements 18 f arearranged such that one mixing element 18 f mounted on the shaft 19 isrotated 90 degrees from the mounting orientation of the adjacent mixingelement 18 f so that the two adjacent mixing elements 18 f may rotatewithout interference from other mixing elements.

Having a plurality of ellipsoid mixing elements 18 f creates a regionwhen the meat is subjected to a massaging action to increase diffusionand ingredient incorporation. While the ellipsoid elements 18 f may beused as a larger zone or region of ellipsoid elements 18 f, they mayalso be employed as a smaller processing area or zone along with otherelements. The massaging action impacts the microstructure and membranetissue of the meat, while maintaining the integrity and larger piecedimensions of the meat that are desired for certain whole muscleproducts. Depending on the configuration of the elements 18, themassaging region may increase ingredient incorporation or may preparethe meat pieces for further processing.

The configuration of elements illustrated in FIGS. 28A-B is similar tothe configuration of FIGS. 26A-B, except that the configuration in FIGS.28A-B lacks the blocking elements 18 e and includes additionalsharp-edged ovate profile elements 18 b. Further, the second and thirdaddition sharp-edged ovate profile elements 18 a displace the proximatecircular-shaped element 18 c by one position. The configuration of FIGS.28A-B also has sharp-edged ovate profile elements 18 a near thedischarge or output end 67, instead of frustoconical elements 18 d asshown in FIGS. 26A-B.

As mentioned, the mixing elements 18 d, 18 e, and 18 f are configured towork the meat while limiting or preventing unnecessary destruction, suchthat the integrity and appearance of the whole muscle meat is retained.The mixing elements 18 d, 18 e, and 18 f may be employed with othermixing elements, such as higher shear elements 18 a and 18 b, toincrease the level of processing done to the ingredients. Having anoptimized selection of mixing elements 18 provides whole muscle meatwith texture and flavor integrity through a process that efficiently andeffectively incorporates the salt solution and other ingredients.

Turning now to the graphical and tabular representations shown in FIGS.29-30, the effects of the mixing elements 18 d, 18 e, and 18 f on thewhole muscle meat are illustrated. FIGS. 29-30 show the resulting meatpiece distribution of a variety of mixing element configurations. FIG.29 shows the results in tabular format, whereas FIG. 30 employs agraphical format. As detailed above it is desirable to have minimalreduction in the size of the meat pieces but also to have significantincorporation of the ingredients, such as having the salt solutiondiffused through the meat pieces. Thus, since FIGS. 29 and 30 illustratemeat piece size, these results illustrate only one of the factors toconsider when determining which element configuration to employ. Toevaluate the configuration's affect on the meat pieces, standard meatchunks were fed into a five inch diameter prototype (the diameter of theopening in the barrel is five inches across). After the meat chunks wereprocessed in the five inch diameter prototype, the resulting meat pieceswere divided up by their particle size. The resulting meat pieces weresorted into the following piece size categories: large, medium, small,and bit sizes. The large size was approximately 16.03 in or bigger. Amedium piece was between approximately 4.01 in² and 16.03 in². A smallpiece of meat measured between approximately 0.72 in² and 4.01 in². Allmeat pieces covering an area smaller than 0.72 in² were considered bitpieces. Once the meat pieces were divided into their respective sizes,the different size categories were weighed. The percentage of thedifferent size categories are illustrated in FIGS. 29 and 30 for variousconfigurations of the mixing elements.

As mentioned, the configuration evaluations were run on a five-inchdiameter prototype and, thus, the distance from the center of the shaftto the barrel wall was 2.5 inches. In preparation, the various mixingelements 18 for each configuration were sized to the five-inch prototypeto ensure movement of the mixture through the housing and encourageingredient diffusion and incorporation into the meat. In the five-inchprototype, the mixing element 18 a of FIG. 3 may have a distance fromcenter to tip of between 2 to nearly 2.5 inches and a thickness betweenabout 0.25 to 2.0 inches. By one approach, the distance from center totip of the element 18 a is 2.44 inches, with a thickness of 1 inch. Theellipsoidal element 18 f manufactured for use in the five-inch prototypemay have a distance from the center to the outer tip of between 1.7 to2.3 inches and a thickness of between 1.5 to 2.5 inches. By oneapproach, the distance from center to tip of the ellipsoidal element 18f is 2.0 inches with a thickness of 2.0 inches. More particularly, thewidth of the ellipsoid mixing element 18 f from one rounded end point150 to the other rounded end point 150 along axis 151 may be between 3.4and 4.6 inches, and in one illustrative embodiment is 4.02 inches. Thelength of the mixing element 18 f from one rim 152 to the other rim 152along axis 153 may be between 1.5 to 2.5 inches, and in one illustrativeembodiment is 2.0 inches. Additionally, the rim 152 may have a diameteralong axis 157, as shown in FIG. 24B. For the five-inch prototype of thefrustoconical element 18 d, the larger diameter end face 130 may measurebetween 3.25 and 3.75 inches, whereas the smaller diameter end face 132may measure between 2.75 and 3.25. The single frustoconical element 18 dmay have about a 1.0 inch thickness and the double frustoconical element18 d may have about a 2.0 inch thickness. In one illustrativeembodiment, the frustoconical element 18 d has a larger diameter endface 130 of 3.38 inches and a smaller diameter end face 132 of 3.0inches. The blocking element 18 e has a length from surface 144 b tosecond surface 146 of between 3.25 and 3.75 inches and a width betweenthe flat sides 144 a of between 2 and 2.5 inches. By one approach, theblocking element has a length of 3.38 inches, a width of 2.25 inches anda distance from the center of the bore to the outside surface 146 of2.19 inches.

In addition to the five-inch prototype, the barrel opening of aproduction-scale mixer may have approximately a 4.0 inch to a 10.0 inchdiameter. By one approach, the production-scale mixer will haveapproximately an 8.0 inch diameter shaft, with a distance from thecenter of the shaft to the barrel wall of 3.94 inches. The elements tobe used in an eight-inch production-scale mixer will be sized to ensuremovement of the mixture through the housing and encourage ingredientdiffusion and incorporation in to the meat, similarly to the five-inchprototype. For example, in the eight-inch diameter shaft, the distancefrom the center of the mixing element 18 a to the tip of the element is3.88 inches, and the distance from the center of the ellipsoidal element18 f to the outer tip is 3.38 inches.

While the results illustrated in FIGS. 29 and 30 show the affects ofdifferent element configurations, the results may vary slightly in alarger-scale mixer, such as the eight-inch production-scale mixer. Sincethe testing apparatus was smaller than the production-scale might be, aportion of the reduction in the size of the meat pieces may be addressedby using a larger scale process. Nonetheless, the results obtained fromthe five-inch prototype provide a comparison of the different mixingelements 18 affects on particle size reduction.

The first column 160 of FIGS. 29 and 30 shows the results of wholemuscle meat processed in the configuration of FIG. 28. The whole musclemeat input into the system was not injected with brine or salt solution.The resulting meat chunks sizes are shown. The second column 162 showsthe results of whole muscle meat processed in the configuration of FIG.26 and the meat processed was injected with salt solution. While bothconfigurations had a significant amount of reduction in the size of themeat chunks, the configuration of FIG. 26 did show a bit less particlesize reduction. Thus, including the blocking elements 18 e and removingsome of the sharp-edged ovate elements 18 a and 18 b appears to lessenthe amount of piece size reduction. In addition, the whole muscleproduct used with the configuration of FIG. 26 (column 162) was injectedwith brine or a salt solution prior to processing. The salt solutionsoftened the muscle pieces such that they were less rigid during theprocessing and may have been able to more easily navigate through themixer without as much decrease in the size of the meat pieces.

The third column 164 and fourth column 166 are results obtained from theconfiguration illustrated in FIG. 27. However, the results in column 166were passed through the mixer housing 20 twice. Thus, while the resultsof column 166 shown some additional reduction in the size of the meatchunks, the meat underwent additional ingredient incorporation. Further,while the 13.57% of the meat chunks were reduced in size from the largerchunks after the first pass, only an additional 5.51% of the largerchunks were reduced in size during the second pass. Thus, while the meatproduct underwent approximately twice the processing, the meat chunksdid not continue to decrease in size at the same rate. Further, themixing element configuration of FIG. 27 caused significantly lessreduction in the size of the meat pieces than the configurations ofFIGS. 26 and 28.

As shown in FIGS. 29 and 30, the mixing element configuration of FIG. 25caused the least reduction in the size of the meat pieces, though onlyslightly less than the mixing element configuration of FIG. 27. Moreparticularly, as shown in column 168, the FIG. 25 configuration resultedin 86.90% of the meat pieces being large, whereas the FIG. 27configuration resulted in 86.43% of the meat pieces being large.However, similar to the single pass of the FIG. 27 configuration, theresulting meat product from the FIG. 25 configuration did not undergooptimal cure distribution and protein extraction. Further, theconfiguration of FIG. 25 resulted in a less than optimal flow rate thatis required to effectively and efficiently push the meat product throughthe mixer housing 20. Finally, the far right column 170 depicts the meatsize distribution for the typical batch whole's muscle processpreviously described.

As mentioned, the need for sufficient cure distribution and proteinextraction must be balanced with muscle piece integrity. Some of theconfigurations tested were either too aggressive or were not aggressiveenough and thus, the element configurations may be adjusted accordingly.For example, meat pieces processed by the configuration of FIG. 28,illustrated in column 160, underwent significant piece size reductionand the configuration of FIG. 28 could be adjusted to lessen the amountof high shear force applied to the meat pieces. Alternatively, wholemuscle meat process in the configuration of FIG. 25 underwent verylittle piece size reduction; however, the meat product produced had notbeen sufficiently worked such that the resulting meat product hadinsufficient cure distribution and protein extraction. The configurationof FIG. 25 may be adjusted to provide more cure distribution and proteinextraction. In sum, depending on the whole muscle meat being processedand the desired ingredient incorporation, an optimal mixing elementconfiguration may incorporate aspects of the FIG. 25 configuration andthe FIG. 28 configuration.

The mixer 10 including the shafts 19 may be manufactured in a variety ofmanners. By one approach, the shaft 19 and the mixing elements 18 areproduced of stainless steel and specifically milled in a unitaryconstruction from a large piece of material. Such a unitary constructionmay permit the mixer to be more easily cleaned. By another approach, theshaft 19 and mixing elements 18 are produced individually as singleelements. Such a construction allows for increased flexibility such thatthe configuration may be easily adapted to a different configuration.These individually produced elements may also be constructed ofstainless steel. By yet another approach, the construction mayfacilitate the use of zones or groupings such that the shaft 19 andmixing elements 18 may be constructed in a few sections. For example,the entire shaft 19 and mixing elements 18 may be constructed in four orfive sections. The chosen mixer construction may depend on the type andvariety of meat products that will be processed, and the conditions inthe plant, to note but a few considerations.

The embodiments described above relate to continuous processing, i.e.,processes in which ingredients are input during discharge of a combinedoutput. In these processes, the input and/or the output steps may beinterrupted periodically or may be intermittent.

From the foregoing, it should be appreciated that the invention providesa new and improved method for effecting protein extraction and mixing ofmeat components for certain processed meat products. The term “meat” isused broadly herein to refer to meat such as beef, pork, poultry, fishand meat byproducts, including cuts or pieces that are all or primarilyall fat, as well as lean cuts or pieces that have relatively higherprotein content. The terms “meat product” and “meat ingredient” are usedbroadly herein to refer to products or ingredients that contain meat,alone or in combination with other components.

The above-described embodiments of the invention are believed to beeffective for achieving rapid protein extraction and mixing of foodcomponents in a much smaller apparatus than that used in certain priorart batch mixing processes. In addition to reducing floor spacerequirements, the preferred embodiments of the invention also may reducecost and cleanup time as compared with these prior art processes andapparatus. The invention may also result in significant cost savings byenabling more precise control of the composition of the combined outputstream.

Those skilled in the art will recognize that a wide variety ofmodifications, alterations, and combinations can be made with respect tothe above described embodiments without departing from the spirit andscope of the invention, and that such modifications, alterations, andcombinations are to be viewed as being within the ambit of the inventiveconcept.

1. An element for a continuous process meat mixer, the elementcomprising: a generally egg-shaped body for use in a continuous processmeat mixer, the generally egg-shaped body having a pair ofellipsoid-shaped portions; three perpendicular axes through thegenerally egg-shaped body including a longer length first axis andshorter length second and third axes; a centrally located bore throughthe generally egg-shaped body for attaching the element to thecontinuous process meat mixer, the centrally located bore extendingperpendicular to the longer length first axis.
 2. The element of claim 1wherein the pair of ellipsoid-shaped portions extend along the firstaxis.
 3. The element of claim 2 wherein the pair of ellipsoid-shapedportions include rounded end points aligned with the first axis.
 4. Theelement of claim 1 wherein the generally egg-shaped body has a widthalong the first axis in the range of approximately 3.4 inches toapproximately 4.6 inches.
 5. The element of claim 1 wherein thegenerally egg-shaped body has a length along the second axis ofapproximately 1.5 inches to approximately 2.5 inches.
 6. The element ofclaim 1 wherein the generally egg-shaped body has a width along thefirst axis, a length along the second axis, and a ratio of the width tothe length in the range of approximately 1.4 to approximately 3.1. 7.The element of claim 1 in combination with a continuous process meatmixer housing having a rotatable shaft therein, the shaft extendingthrough the bore of the generally egg-shaped body perpendicular to thefirst axis of the generally egg-shaped body.
 8. The element of claim 7wherein the mixer housing includes a barrel having an inner diameter andthe shaft has a centerline spaced from an interior surface of the barrelby a clearance distance, the ratio of the barrel inner diameter to theclearance distance being approximately
 2. 9. An element for a continuousprocess meat mixer, the element comprising: a generally egg-shaped bodyfor use in a continuous process meat mixer; three perpendicular axesthrough the generally egg-shaped body including a longer length firstaxis and shorter length second and third axes; a centrally located borethrough the generally egg-shaped body for attaching the element to thecontinuous process meat mixer, the centrally located bore extendingperpendicular to the longer length first axis, wherein the generallyegg-shaped body includes a cylindrical portion having a diameter alongthe third axis.
 10. A mixing element for a meat mixer, the elementcomprising: a body having a length; a pair of rim portions of the bodyat opposite ends thereof; a throughbore extending along the length ofthe body, the throughbore configured to receive a shaft therethrough;and a protuberance extending perpendicular to the length of the body andaway from the throughbore, the protuberance having a roundedconfiguration without edges such that the protuberance is adapted formassaging whole muscle meat while preserving the structural integrity ofthe whole muscle meat, the protuberance having a decreasingcross-section as the protuberance extends away from the throughbore anda base portion adjacent the body that extends from closely adjacent onerim portion to closely adjacent the other rim portion along the lengthof the body.
 11. The mixing element of claim 10 further comprising asecond protuberance extending perpendicular to the length of the body,the second protuberance having a rounded configuration without edges.12. A mixing element for a meat mixer, the element comprising: a bodyhaving a length; a throughbore extending along the length of the body,the throughbore configured to receive a shaft therethrough; aprotuberance extending perpendicular to the length of the body and awayfrom the throughbore, the protuberance having a rounded configurationwithout edges such that the protuberance is adapted for massaging wholemuscle meat while preserving the structural integrity of the wholemuscle meat, the protuberance having a decreasing cross-section as theprotuberance extends away from the throughbore; and a secondprotuberance extending perpendicular to the length of the body, thesecond protuberance having a rounded configuration without edges,wherein the first and second protuberances are aligned along a commonaxis extending perpendicular to the length of the body.
 13. The mixingelement of claim 10 wherein the body has a cylindrical portion and theprotuberance extends outward from the cylindrical portion.
 14. Themixing element of claim 13 wherein the body has a curved transitionportion extending between the cylindrical portion and the protuberance.15. A mixing element for a meat mixer, the element comprising: a bodyhaving a length; a throughbore extending along the length of the body,the throughbore configured to receive a shaft therethrough; and aprotuberance extending perpendicular to the length of the body, theprotuberance having a rounded configuration without edges such that theprotuberance is adapted for massaging whole muscle meat while preservingthe structural integrity of the whole muscle meat, wherein theprotuberance includes an ellipsoid-shaped portion having a rounded endpoint.
 16. The mixing element of claim 15 further comprising a secondprotuberance extending perpendicular to the length of the body, thesecond protuberance having a rounded configuration without edges. 17.The mixing element of claim 16 wherein the first and secondprotuberances are aligned along a common axis extending perpendicular tothe length of the body.
 18. A mixing element for a meat mixer, theelement comprising: a body having a length; and a protuberance extendingperpendicular to the length of the body, the protuberance having arounded configuration without edges such that the protuberance isadapted for massaging whole muscle meat while preserving the structuralintegrity of the whole muscle meat, wherein the protuberance includes anellipsoid-shaped portion having a rounded end point, and wherein thebody includes a cylindrical portion having a diameter extendinggenerally perpendicular to the length of the body.